The present invention relates to waterproof footwear, and in particular to a shoe or a boot with a waterproof upper and a sole made of a plastic or rubber material. The present invention also relates to a process for manufacturing said footwear.
Known articles of waterproof footwear comprise a sole, which is injection-molded together with an insole sewn with the lower edges of an upper, and a protective lining comprising one or more fabric layers coupled with one or more semi-permeable membranes, i.e., membranes which can be crossed by steam, not by water. In these known articles of footwear, the upper, especially if made of leather, may absorb water. This water thus penetrates the upper through the seam with the insole, thereby going around the protective lining.
For avoiding this drawback, U.S. Pat. No. 4,899,465 discloses a waterproof footwear, the upper of which is joined to the insole by means of a perforated portion or a net tape. During the sole molding, a portion of plastic or rubber material separates the upper from the insole, thereby preventing the water from passing through them. However, also in this known footwear, the water may cross the upper, so as to be absorbed by the outer fabric of the lining and pass, also if in a reduced way, inside the footwear through the seam of the insole. Furthermore, it is relatively complex to carry out the holes in the upper and the net tape is quite wide and rigid and thus hampers the sole bending.
For avoiding these further drawbacks, U.S. Pat. No. 5,505,011 discloses a waterproof footwear similar to the previous one, with the exception that the lower edge of the upper is not perforated or provided with nets. Rather, it is directly glued to the protective lining, which is prolonged up to the insole and sewn to it. However, also in this known footwear, very small quantities of water filter through the upper and may stagnate in the interspace between the lining and the upper.
DE 4004674 discloses a waterproof footwear wherein a waterproof tape is glued along the outer lower edge of the upper, so as to allow minimum water penetration through the upper. DE 3840263 discloses a waterproof footwear wherein a sealing tape is sewn along the inner lower edge of the upper and the hot-welded to a membrane. This manufacturing process is relatively difficult to perform due to the relative positions of upper, tape and membrane.